VISCOUS INVISCID INTERACTIONS OF THE FOREBODY FLOWFIELD OF AN AIRBREATHING HYPERSONIC VEHICLE/

A hypersonic cruise missile, which can be launched from conventional a ircraft or from surface based assets and which can cruise at a Mach nu mber of 8, requires at least two propulsion systems: a rocket-based pr opulsion system and a supersonic combustion ramjet system. The inlet t o the airbreathing propulsion system will be closed during that portio n of the flight powered by the rocket based propulsion system. As a re sult, a shock-wave/boundary-layer interaction Kill result when the sup ersonic Bow on the forebody encounters the compression ramp formed by the closed inlet. To investigate the flowfield for this interaction, s urface-pressure measurements and flow-visualization photographs have b een obtained during an experimental program conducted in the Tri-Sonic Wind Tunnel at the U.S. Air Force Academy. Data were obtained at a fr eestream Mach number of 4.28 and at a freestream Reynolds; number (bas ed on the model length) of 12.79 x 10(6) over an angle-of-attack range from -7.3 to +7.3 deg. The data are compared with computations made w ith version 3 of the General Aerodynamic Simulation Program. The three -dimensional viscous/inviscid interaction that occurs near the compres sion ramp contains transverse vortices and streamwise vortices, with p ressures in the reattachment region being approximately an order of ma gnitude larger than those for the undisturbed flow upstream of the int eraction.